Cannabis for Mental Health and Addiction: Potency, Regulation, and Neurobiological Insights with Dr. Hsu

This podcast episode features Dr. Michael Hsu, a psychiatrist from Brigham Women's Hospital and Harvard Medical School, discussing the complex landscape of cannabis use for mental health, addiction, and its evolving potency. Dr. Hsu and Dr. K emphasize the importance of acknowledging personal biases and values when approaching the topic, highlighting that the "right" answer for one individual may not be for another. They begin by clarifying terminology, distinguishing between whole-plant cannabis (containing hundreds of cannabinoids like Delta-9 THC, CBD, and Cannabinol) and distilled cannabinoids (like synthetic Dronabinol or FDA-approved Epidiolex). This foundational understanding is crucial given the vast differences in products available.

A significant portion of the discussion focuses on the dramatic increase in cannabis potency over time. Historically, cannabis contained 2-3% THC, rising to 3-5% in the 1960s-70s. Today, whole-plant cannabis can reach 20-30% THC, with vapes and other concentrates hitting 60-90%, representing a 10- to 30-fold increase. This escalation is attributed to the cannabis industry, which, influenced by "Big Tobacco" marketing tactics, capitalizes on demand for higher potency, mirroring trends seen in the opioid crisis where increased potency (e.g., fentanyl) leads to greater addiction and harm. This commercial drive for stronger products complicates research and therapeutic applications.

The episode directly addresses the myth that marijuana cannot be addictive, presenting clinical evidence that cannabis addiction is real, particularly with frequent use and high THC content (affecting about 30% of frequent users). Signs of addiction include early morning cravings, continued use despite negative consequences (e.g., impaired work), and escalating doses. While some individuals report using cannabis for conditions like anxiety, depression, or PTSD, Dr. Hsu cautions against self-medication with unregulated products. He highlights that studies on whole-plant cannabis for PTSD show worsening symptoms with increased use, and improvement upon cessation, contradicting anecdotal reports.

Neurobiologically, THC interacts with CB1 receptors in the brain, including the amygdala (the fear center). At low doses, THC can have an anxiolytic (anxiety-reducing) effect, but at higher doses, it becomes anxiogenic (anxiety-generating), potentially causing anxiety or traumatic responses. The discussion also touches on CBD's potential for anxiety, noting that therapeutic doses are in the hundreds of milligrams, far exceeding the 5-10mg found in many unregulated dispensary products. A study from Mississippi revealed severe inconsistencies in CBD product labeling, with many containing little to no actual CBD, underscoring the significant role of the placebo effect in reported benefits. The dangers of synthetic cannabinoids like K2, which can induce severe paranoia and psychosis, further illustrate the risks of unregulated, high-potency substances.

"it's still a schedule one drug meaning it has high abuse potential in the same category as lsd"

"if i'm using a substance to numb my emotional state my brain's ability to control and regulate my emotional state becomes less necessary"

"the truth is probably somewhere in the middle"

"the products that we're talking about today that are people are using and wondering if it could be helpful for mental health purposes are totally different from the things that you know we were talking about back in those days"

"the average nowadays is like 20 30 and certain vapes can even go up and other products can go up to 60 90 so we're talking the products that we're talking about today that are people are using and wondering if it could be helpful for mental health purposes are totally different from the things that you know we were talking about back in those days"

"people that do use it frequently say over two or three times a week we see around like 30 percent of people developing an addiction to it"

"in the studies that we have for social anxiety and other anxiety and depression especially we'll just focus on cbd for now... what we see is that oftentimes you know in order to get a therapeutic effect you need a certain on on a magnitude of like hundreds of cbd milligram and milligrams to sort of get the desired effect of some of these products"

"only three out of 25 of those products specifically in that area had cbd content that was like within 20 of what they were saying"

"what we've seen is that you know in studies for example there are two big studies out of the veterans affairs hospitals where they tracked people who had ptsd symptoms and started using cannabis and over time people who use more cannabis and more and used it more frequently this is again talking about whole plant smoked cannabis the higher thc content and the more that they were using it the worse and the worsening of their symptoms over time"

"at low doses of thc what happens is that there seems to be sort of an anxiolytic effect to the to cannabis... but what happens is that at higher doses of thc the effect on the cb1 receptor actually flips we see that it can create anxiogenic effects on the amygdala"